1. Field of the Invention
The present invention relates to an improved support system for an aircraft landing gear trunnion, and in particular to a support system which permits movement of the landing gear farther out from the aircraft body without a loss in landing gear stiffness, and which provides for protection of control lines extending through the wing against damage in the event a landing gear is severed from the aircraft.
2. Description of the Prior Art
In low wing, swept wing airplanes the main landing gears are usually carried on trunnions having fore and aft axes. The forward ends of the trunnions are carried on the rear wing spar and the aft ends are carried on a variety of types of structure.
Aircraft overall efficiency, as influenced by weight and balance factors, is improved for certain aircraft configurations by locating the main landing gear so far aft of the rear wing spar that it complicates the structural problem of landing gear attachment. Also, the combination of (1) a landing gear length great enough to provide adequate clearence for under wing engines and for the tail at liftoff and (2) the necessity of stowing the wheels in the underbody dictates a wide thread which further complicates gear attachment. A third complicating factor is that the fore and aft trunnion bearings must be far enough apart and held in stiff enough structure to contribute adequately to fore and aft gear stiffness. A limber gear interferes with efficient anti-skid operation.
There are two well known landing gear attachment structure arrangements. The first involves use of a cantilever structure extending rearwardly from the rear wing spar to mount the aft end of the trunnion. The second involves the use of a landing gear beam disposed rearwardly of the rear wing spar, extending from a connection with the body frame outwardly to a connection with the rear wing spar. An attempted use of either arrangement for supporting a landing gear trunnion at a location that is spaced both farther out on the wing and farther aft of the rear wing strut than the conventional trunnion location would present a problem. A landing gear beam would become too flexible and/or too heavy because, to accomodate the landing gear position, it must be made both longer and shallower in order to fit within the wing envelope. A cantilever support becomes thinner because the air foil section is thinner at the more aft low location. Making the cantilever structure stiff enough, if possible, would require excessive weight.
A principal object of the present invention is to provide a new structural concept for supporting the aft end of a landing gear trunnion, permitting the use of a lightweight, structurally stiff mounting for a wide thread, and as further aft and further out positioning of the main landing gear, and further providing for the protection of control lines extending through the wing in the event of a loss of a landing gear.